Important applications of current interest require that the relative phase of an incident fringe pattern vis-a-vis a fixed reference be determined. Such fringe patterns are developed, for example, by interference between split components of a coherent light beam and are used for purposes per se well known, e.g., to measure small distance displacements, surface contours or irregularities, object shapes and forms, and the like.
It is an object of the present invention to provide an improved electro-optical processing apparatus.
More specifically, it is an object of the present invention to provide an electro-optical system for measuring the phase or phase shift of a wave fringe pattern.
It is another object of the present invention to provide electro-optical fringe phase detection apparatus which averages a phase measurement over plural cycles (wavelengths).
Yet another object of the present invention is the provision of fringe pattern phase measurement structure operable on a time variable basis to obviate processing of bias or direct current signal constituents.
A still further object of the present invention is to provide electro-optical apparatus for effecting complex multiplication.